Presence of β-Lactamase-producing Enterobacterales and Isolates in Marine Mammals.

Marine mammals have been described as sentinels of the health of marine ecosystems. Therefore, the aim of this study was to investigate (i) the presence of extended-spectrum β-lactamase (ESBL)- and AmpC-producing Enterobacterales, which comprise several bacterial families important to the healthcare sector, as well as (ii) the presence of in these coastal animals. The antimicrobial resistance pheno- and genotypes, as well as biocide susceptibility of Enterobacterales isolated from stranded marine mammals, were determined prior to their rehabilitation. All isolates ( = 27) were screened for virulence genes via DNA-based microarray, and twelve selected isolates were analyzed by whole-genome sequencing. Seventy-one percent of the Enterobacterales isolates exhibited a multidrug-resistant (MDR) pheno- and genotype. The gene ( = 51) was the predominant β-lactamase gene. In addition, ( = 38), ( = 8), ( = 7), ( = 7), ( = 3), and ( = 2) were detected. The most prevalent non-β-lactamase genes were ( = 38), ( = 34), ( = 34), and (A) ( = 34). isolates belonging to the pandemic sequence types (STs) ST38, ST167, and ST648 were identified. Among isolates ( = 18), . Havana was the most prevalent serotype. The present study revealed a high prevalence of MDR bacteria and the presence of pandemic high-risk clones, both of which are indicators of anthropogenic antimicrobial pollution, in marine mammals.